Protective starting device for internal combustion engines



March 3 1959 M. VON KlENLlN ETAL PROTECTIVE STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed Jun e 3, 1955 2 Sheets-Sheet 1 INV N TORS. MARKUS l/ON IENLIN.

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ATTOR/V K March 31, 1959' M. VON KlENLlN ETAL 7 2,879,754 PROTECTIVE STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Filed June 3, 1955 2 Sheets-Sheet 2 m m L: m.

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PROTECTIVE STARTING DEVICE FOR INTERNAL COMBUSTION ENGINES Markus Von Kienlin, Richard Seifert, and Walter Barth,

Friedrichshafen, Germany, assignors to Maybaeh- Motorenbau G.m.b.H., Friedrichshafen, Germany, a German firm Application June 3,1955, Serial No. 513,120 Claims priority, application Germany June 9, 1954 2 'Claims. Cl. 123-140 The present invention relates to a protective device for an internal combustion engine having a pres sure oil actuated fuel admission regulator, and a starting oil pump driven by a source of power independent of the internal combustion engine for supplying lubricating oil as well as pressure oil for actuating the regulator.

The fuel admission regulator tends to fully open the fuel admission while the engine is standing still. Therefore, excessively high ignition pressures may be produced by the first ignitions when the engineis started; these excessive pressures may cause damage.

It is an object of the present invention to protect the engine in a simple manner against excessive ignition pressures during starting of the engine. According to the invention, an auxiliary piston is actuated by the oil pressure produced by the starting oil pump; The auxiliary piston moves a locking member-into the path of the fuel admission regulating member, blocking the latter at a position in which it admits no more fuel to the engine than is necessary to start the engine. Therefore no excessively high ignition pressures can occur when the engine is started. By limiting the movement of the fuel admission regulator, the engine receives only the amount of fuel which produces normal ignition pressures.

The novel features which are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself however and additional objects and advantages thereof will best be understood from the following description of an embodiment thereof when read in conjunction with the accompanying drawing, in which- Figure 1 is a diagrammatic part sectional illustration of a system according to the invention in engine starting position.

Fig. 2 shows the system illustrated in Fig. 1 in the position when the engine is at rest.

Fig. 3 shows the system in the position when the engine operates at full load.

Like parts are designated by like numerals in all figures of the drawing.

Referring more particularly to the drawing, numeral 1 designates an internal combustion engine whose shaft 2 drives a pressure oil pump 5 through gear wheels 3 and 4. Mounted on the shaft 2 is a conventional centrifugal governor comprising a yoke 6" pivotally supporting elbow levers 6, one end of which is provided with a weight 6, the other end resting on a sleeve 8' which is axially movable relatively to the shaft 2. The axial movements of the sleeve 8 are transmitted through a ball bearing to a flange 8 which is at one end of a rod 8". The other end of the rod 8" is provided with a disc resting on a spring 7. The flange 8 abuts against one arm of an elbow lever 9 having a stationary fulcrum 9'. The other arm of the lever 9 is pivoted to one end of a connecting rod 10, the other end of the connecting rod being pivoted to the stem of a piston valve 11 forming part of a pressure oil actuated fuel admission regulator. The valve 11 moves against the pressure of a spring 12 in a hollow cylindrical ice extension of a follower piston 14 and controls the flow of pressure oil coming from the pump 5 through a conduit 17 to the lower surface of the piston 14 through ports 15 from an annular chamber 16in a stationary casing 13. The follower piston 14 moves against the pressure of a spring 18, actuating an elbow lever 19 which moves a lever 21 through a link 20. The lever 21 is mounted on a shaft 22, which is connected through means, not shown, withthe fuel injection pumps or with fuel injection devices, not shown, for controlling the fuel admission.

Numeral 23 designates an electric motor which drives a. starting pump 24' for supplying pressure oil through a check valve 25 into thev conduit 17 and into a conduit 26 before the internal combustion engine is started. The motor 23'is supplied with current by a battery 34 through Wiring controlled by a switch 33; Conduit 26 is connected with a cylinder 27 containing a piston 28. The latter actuates a locking lever 29 having a thumb 30 adapted to rest on a collar 31 on the rod 10 for limiting upward movement of the rod. A spring 32 holds the lever 29 on the rod of the piston 28 and presses the latter downward when there'is no pressure oil below the piston 28.

The protective starting deviceacts as follows: Prior to starting the internal combustion engine 1, the weights 6 of the centrifugal governor are in the positions shown in Fig. 2 by gravity. and/or by the action of the spring 7.

. The spring 12 pulls on the lever 9 and presses the latter against the flange 8, simultaneously holding the valve 11 in the uppermost position, affording flow of pressure oil from the conduit17 through the ports 15 to the underside of the piston 14;" I, v I For startingl theplant, the switch 33 is closed, as shown in Fig. 1, and the motor'23 is started so that the oil pump 24 is operated. The latter supplies the lubricating oil circuit, not shown, of the engine through a conduit 17' as well as the control conduit 17 through the check valve 25 and the conduit 26 with pressure oil. The oil moves the piston 28 in the cylinder 27 upward into the illustrated position. This causes downward movement of the thumb 30 acting on the collar 31 on the rod 10 and movement of the piston valve 11 from the position shown in Fig. 2 to the position shown in Fig. 1. The piston 14, forced upward by the pressure fiuid coming from the pipe 17, can overcome the pressure of the spring 18 only until it has reached the position shown in Fig. 1 and the piston 14 cannot move farther than shown in Fig. 1 because in this position the upper part of the valve 11 closes the ports 15 so that no more pressure fluid is admitted to the underside of the piston 14. The position of the piston 14 shown in Fig. 1 corresponds to a fuel admission A in contradistinction to the full fuel admission H which would prevail if the plant were not equipped with the protective device according to the invention. Admission A corresponds to about 40% of full fuel admission H. The position of the lever 21 for idling of the engine is marked by the letter L.

The engine can now be started by means of a conventional starting device, not shown. Since the fuel admission has been set at A instead of at full admission H, the engine cylinders do not receive more fuel than needed for starting so that no unduly high ignition pressures are produced during the first revolutions which pressures may damage the mechanism.

When the engine 1 is in operation the system is in the position shown in Fig. 3 and the pump 5 produces the required oil pressure whereby the check valve 25 is closed. The electric motor 23 can now be stopped by opening the switch 33 which may be done automatically by conventional means, not shown, in response to the oil pressure produced by the pump 5. When the check valve 25 is closed and the pump 24 is stopped, the conduit 26 is without pressure so that the piston 28 is moved to its lower position due to the action of the spring 32. The locking thumb 30 is moved upwards and out of the way of the collar 31 so that the automatic fuel admission control can operate normally. The governor 6-9 can now push the valve 11 to its uppermost position, assuring that there is always pressure oil suppliecl from the conduit 17 to the underside of the piston 14. This is not possible when the device is in the starting position shown in Fig. 1. Fig. 3 shows the valve 11 in the uppermost position in which the piston 11 has again closed the ports 15. If, for example, due to leakages the pressure below the piston 14 becomes so low that the spring 18 can push the piston 14 downwards, the ports 15 are opened, admitting pressure oil so that the mechanism '14, 19, 20 is returned to the full load position H and the ports 15 are again closed.

If the speed of the engine 1 increases while the fuel admission is set for full load or part load, the weights 6 tend to move outwards, pressing thefflange 8 to the left and swinging the lever 9 counterclockwise. This causes downward movement of the rod 10 and of the valve 11 whose upper edge opens the ports 15 allowing pressure fluid to escape from the underside of the piston 14 through vents 35. The spring 18 can now push the piston downwards and, through the mechanism 19''2 1, turn the shaft 22 counterclockwise for reducing the fuel admission to a rate between full load H and starting A, i.e., 'to one corresponding to the load. 7 4

When the engine isstopped the system assumes the position shown in Fig. 2. The spring 7 moves the flange 8 to the right, allowing the lever 9 to move clockwise and the spring 12 to move the piston 11 upwards for fully opening the ports 15 to the flow of oil under pressure from the pipe 17 so that the system is ready for restarting.

When idling, the engine shaft rotates at relatively high speed, causing the centrifugal governor to swing lever 9 counterclockwise and the piston 11 to moveto lowermost position so that the ports 15 are opened and the pressure fluid below the piston 14 can escape through the ports 35. The spring 18 can now press the piston downward so that the lever 19 swings counterclockwise and moves the lever 21 into the idling position L.

What is claimed is:

1. A protective starting system for an internal combustion engine comprising a governor responsive to the speed of the engine, actuating means for actuating control means for the fuel admission to the engine, a mechanism interconnecting said governor and said actuating means, locking means including a member adapted to engage said mechanism for preventing movement thereof beyond a position in which the fuel admission is greater than that required for starting the engine, said locking means including a piston reciprocable in a cylinder and connected with said member for moving said member into and out of engagement with said mechanism, a starting oil pump, a source of power independent of the internal combustion engine and connected with said oil pump for driving the latter, and a pressure oil conduit connecting said oil pump with said cylinder for moving said piston and thereby said member into engagement with said mechanism as long as said source of power is in operation. I

2. A system as defined in claim 1 including a conduit connected with said starting oil pump for supplying lubrieating oil to the engine.

References Cited in the file of this patent UNITED STATES PATENTS 

